The present invention relates to ultrasonic imaging techniques, and in particular to “parametric” ultrasound imaging that characterizes parameters of the scanned tissue using information in the echo signal other than or in addition to echo amplitude.
Ultrasound imaging is widely regarded as a safe, cost-effective, and versatile medical imaging modality. In a typical echo-mode ultrasonic device, an ultrasonic signal is transmitted into the patient from a transducer and an echo signal is received from the patient and analyzed. In conventional B-mode imaging, only the amplitude of the echo signal is extracted and displayed.
In parametric ultrasound imaging, additional information is extracted from the echo signal beyond its amplitude. This information may include frequency and/or phase information of the echo signal and may be processed to characterize the “effective scatterers” of the tissue through a description of their shape, size, spacing, and density.
Such parametric measurements have a high degree of statistical fluctuation, which limits their practical use in medical diagnostics.